The present invention relates to an imaging method using a magnetic resonance imaging apparatus (hereinafter abbreviated to an MRI apparatus) and more particularly to a method for imaging a fluid flow in a human body, that is, a method of angiography.
As a conventional method for imaging a fluid flow with an MRI apparatus, a method for obtaining a target image from a plurality of images having different properties is known as represented by an example that only a fluid flow is extracted by subtraction of two images such as an image which is obtained by a flow-sensitive pulse sequence and an image which is obtained by a non-flow-sensitive pulse sequence. One of the methods is described in Magnetic Resonance in Medicine 12, pp. 1 to 13 (1989). According to this method, a fluid flow image can be obtained by subtraction of images which are obtained by two measurements when a waveform of a readout gradient magnetic field is changed to a flow encode pulse in which the phase rotation of magnetization in the fluid flow under the gradient field is enhanced and when it is changed to a flow compensation pulse in which the phase rotation of magnetization in the fluid flow under the gradient field is compensated.
According to the above prior art, the waveform of the readout gradient field is different between the flow sensitive pulse sequence and non-flow-sensitive pulse sequence, so that two measurements are necessary. Furthermore, according to the prior art, the measuring time is long and two measurements are necessary, so that there is a problem imposed in obtaining a blood flow image of a dynamic part such as a heart.